Method of mounting plates to printing machine cylinders



Dec. 19, 1967 Y J. OBRIENI MIDDLETON 3,353,598

METHOD OF MOUNTING PLATES TO PRINTING MACHINE CYLINDERS 2 Sheets-Sheet 1Filed Jan. 7, 1966 INVENTOR JOHN 0.7 MIDDLETON By ATTORNEY Dec. 19,19-67 J. OB-RIEN MIBDLETON 3,358,598

7 METHOD OF MOUNTING PLATES TO PRINTING MACHINE CYLINDERS Filed Jan. 27,1966 2 Sheets-Sheet 2 INVE N TOR JOHN 0. MIDDLETON TTOKNEY United StatesPatent 3,358,598 METHOD OF MOUNTING PLATES T0 PRINTING MACHINE CYLINDERSJohn OBrien Middleton, 1303 Lewisham Drive, Clarkson, Ontario, CanadaFiled Jan. 27, 1966, 591'. No. 523,437 4 Claims. (Cl. 101-378) ABSTRACTOF THE DISCLOSURE 'for proper alignment of the plates, such provingbeing followed by indexing of the backing sheet in registration withindex means carried on the machine cylinder.

This invention relates broadly to the field of printing and moreespecially to procedures involved in preparing printing equipment ininstances where batches of particular items are required to be producedfrom time to time.

More particularly, the present invention is directed to an improvementin the presently used methods of mounting rubber or similar printingplates on the rolls or cylinders of rotary-press printing machines. Theinvention herein disclosed also encompasses a new and novel printingplate assembly.

As will be Well appreciated by those skilled in the art, rubber and/ orsynthetic rubber plates are considerably less expensive than othertypes. However, rubber plates pose a serious problem in use, especiallyin multi-colour operations, due to their susceptibility to distortion.For this reason, such plates are formed and mounted individually aroundthe periphery of associated printing cylinders to avoid accumulation ofdistortion which would arise through successive interconnected plates.

Naturally, again referring to multi-colour operations, where a number ofplates are mounted on a single cylinder, to print one colour, successivecylinders bearing plates for other colours must be very accuratelyaligned with respect to one another in order to produce the desiredcomposite print. It is therefore obvious that makeready times areconsiderable and present substantial overhead costs.

When one considers that each individual plate must be positioned on itsassociated cylinder; test or proving runs made; realignment effected andso on, it will be seen that, in instances where a specific printingoperation must be repeated at spaced intervals of time, and suchrepetition is unavoidable in many businesses, a company must choose oneof two courses of action.

Firstly, the company can purchase a very large number of cylinders suchthat an initial set-up may be stored for further use while a ditferentcylinder assembly is used for another printing operation, or, secondly,the said company must accept the expense of repeated make-readyprocedures.

The first course of action calls for a very substantial capitalinvestment plus the necessity of utilizing valuable space for storagepurposes.

The second course of action is, of course, just as objectionable as thefirst, for obvious economic reasons.

3,358,598 Patented Dec. 19, 1967 It is known that efforts have been madefrom time to time in order to provide a simple and rapid means formounting and dismounting plates without requiring immense capital outlayin equipment and storage space. However, to this applicants knowledge,no successful method or apparatus has heretofore been devised. As far asis known, most firms employed in printing and utilizing rotary-pressequipment and rubber or like plates, still mount such plates directlyonto the cylinders and remove a first set of plates on completion of onetask to make way for a new set thus making the best use of a limitednumber of cylinders. Naturally, frequent mounting and removal ofprinting plates, especially rubber or similar plates, results in rapiddeterioration thereof in addition to the considerable expenses involvedin non-productive make-ready procedures.

The applicant has overcome the prior art ditficulties by a novel methodwherein the printing plates are mounted on a detachable backing sheet orplate wrapped around the cylinder. Appreciating the fact that thesecylinders frequently operate at approximately 900 r.p.m., it wouldappear at first glance, that a very substantial locking means would berequired to maintain the backing sheet in registered position on itsassociated cylinder. Surprisingly, however, the applicant hasestablished that a longitudinal adhesive strip affixed to the cylinderwill effect the desired result of maintaining a backing sheet in adesired registered position while presenting a minimum of inconveniencein detaching or temporarily releasing the backing strip for alignmentand registration adjustments.

According to the present invention, during an initial make-readyprocess, index means are provided on both the cylinder and the backingsheet such that following completion of a first run When the backingsheet and the plates secured thereto are removed from the cylinder as aunit, the backing sheet assembly may be remounted in proper registrationwith a minimum of time and effort at a later date.

In addition to the foregoing, the backing sheet and plate assembly maybe conveniently stored in flat condition, thus minimizing storageconsiderations.

In practice, this invention has made it possible for remounting times tobe cut down by as much as of the initial make-ready time.

It is an object of the present invention to provide a new and novelmethod of detachably mounting printing plates on printing cylinders orrolls to permit remounting thereof in specifically desired registrythereon.

It is a further object of the invention to provide a method ofdetachably mounting printing plates on printing cylinders such thatsubsequent remounting of the plates, in proper registry, may be effectedwith rapidity, ease and economy, while storage of the printing plateassemblies is reduced to something akin to the filing of correspondencefiles and the like.

A still further object of the invention resides in provision of animproved printing cylinder and plate assembly wherein the plate assemblymay be stored separately, in flat condition, while the cylinder isemployed in a different printing task in combination with a furtherplate assembly. Another object of the present invention is the provisionof a method of detachably mounting printing plates on printing cylinderssuch that the life expectancy of the printing plates per se isconsiderably increased.

Further objects and advantages will become apparent as the descriptionproceeds with reference to the ap ended drawings wherein:

FIGURE 1 is a perspective view of a cylinder and a backing plateexploded therefrom in flat condition;

FIGURE 2 is a perspective view of acylinder with ,a

backing plate registered thereon immediately prior to wrapping of theplate around the cylinder;

FIGURE 3 is a perspective view of the cylinder and backing plateassembly in operative condition;

FIGURE 4 is a perspective, exploded view of a refined embodiment of theinvention wherein a base sheet is ap lied to the cylinder beforemounting of the backing sheet;

FIGURE 5 is a perspective view of a cylinder with base sheet applied anda strip of adhesive partially applied;

FIGURE 6 is a cross section taken along the lines 65 on FIGURE 5;

FIGURE 7 is a cross sectional view taken along the lines 77 of FIGURE 5;

FIGURE 8 is a perspective view of the assembly of FIGURE 4 in assembledcondition.

Referring initially to FIGURES l, 2 and 3 of the drawings, these figuresdisclose the general concept of the invention wherein a cylinder orroll, for use on a rotary press, is adapted to carry, in cooperationwith the backing sheet, removable image transfer means properlypositioned thereon for imprinting, and wherein provision is made in theinitial make-ready procedure for indexing the backing sheet tofacilitate repositioning thereof on the cylinder when re-runs arerequired.

With more particular reference to FIGS. 1, 2 and 3, a cylinder 1includes a cylindrical backing sheet receiving surface 6, and raisedshoulders 7, 7 extending around the periphery of the cylindrical surface6 at each end thereof and substantially at right angles to the axis ofthe cylinder "1.

Since only one shoulder is actually used, as will hereinafter be morefully described, it is, in practice, only necessary to provide oneshoulder at one end of the cylinder.

A first index means 10 is provided on an enlarged portion 11 of thecylinder 1 adjacent to a shoulder 7. Such index means generally takesthe form of a fine scribe mark although other known indexing expedientscould be used. It should also be noted that indexing means could also beformedon the cylindrical surface 6.

A strip of pressure sensitive adhesive 12' is carried on the cylinderand extends longitudinally of a cylindrical surface 6 for purpose to belater described. The adhesive used may be of any suitable type,preferably capable of revitalization to avoid the necessity of frequentreplacement.

The backing sheet 14 comprises a transparent, rectangular sheet ofplastic material,- such plasticmaterial must be flexible, to permitwrapping of the sheet around the cylinder, but non-deformable under theapplication of normal printing stresses and inert to attack by printinginks and solvents. Polyethylene terephthalate resin sheet has been foundto be suitable for this purpose. Conveniently, the backing sheet issubstantially rectangular and of a thickness slightly less than theheight of the shoulder.

In its assembled position on the cylinder 1, 'a side edge 15 of backingsheet 14 abuts a shoulder 7 of the cylinder 1. =Dueto the fact that theshoulder 7 is slightly higher than the upper surface of the backingsheet, there is less likelihood of the sheet slipping over the shoulderand thus rendering the mounting operation more difficult. It should benoted that the particular shoulder 7 used in the initial make-readyoperation should be identified in order that the same shoulder is alwaysused in remounting plate assemblies. The backing sheet 14 is of suchlength that when it is wrapped about the cylinder 1, the top and bottomends 16 and 17 thereof, will be in substantially edge abuttingrelationship and secured in position on the strip of adhesive 12.

To mount the image transfer means in proper remountable position on thecylinder 1,.the. backing sheet 14 is first wrapped about the cylindricalsurface 6 with its side edge 15 abutting the first shoulder 7 on thecylinder 1 and with its ends 16 and 17 in substantially edge abuttingrelationship overlapping the adhesive strip '12 'and adhered thereto.The backing sheet is, of course, mounted as snugly as possible aroundthe cylinder. Index means 24 are then marked on the backing sheet inregister with the first-mentioned index mark 10 on the cylinder. Theimage transfer means 4 comprising rubber or similar printing plates aredetachably adhered to the backing sheet 14. Conventional provingprocedures are then carried out, as is well known, until the plates areall in desired position on the backing strip and hence on the cylinder.At this stage, the peripheral edges of the plates are sealed with asuitable solvent based neoprene cement or adhesive of the contact typesuch as that known in the trade as Anchor-Weld to prevent access ofprinting ink and solvents to the adhesive by which the plates aremounted on the backing sheet. Since the backing sheet was mounted in aparticular registration with the cylinder 1, the backing sheet 14 maynow be removed from the cylinder 1 with the plates properly aligned andsealed thereon, and may be replaced on the cylinder, in proper registerthereon, by urging the side edge 15 against the indexed shoulder 7 onthe cylinder 1 and wrapping the backing sheet 14 tightly about thecylindrical surface 6 with the first index means 10 on the cylinder 1and the second index means 20 on the backing sheet 14 in registration.From this point, proving is very readily effected since all plates arein proper alignment with one another. This feature is most importantwhere a series of cylinder assemblies are used simultaneously to effectmulti-colour printing operations.

Prior to printing, the longitudinal abutting ends 16 and 17 of thebacking sheet 14 and the side edges thereof are sealed, as were theplates, to prevent ink and solvent from penetrating to the underside ofthe backing sheet.

Turning to the embodiment illustrated in FIGS. 4 to' 8 inclusive, itwill be seen that this further embodiment, while obviously directed tothe same invention, introduces precautionary measures particularlynecessary where a large number of plates are to be mounted in closelyspaced adjacency around the periphery of the printing cylinder.

In view of the previous remarks relating to the extreme accuracyrequired in mounting the plates, it will be appreciated that if, fromnecessity, at least one plate must be mounted in overlapping relation tothe strip of adhesive 12, the slight increase in height at this pointwill create a problem in alignment. In order to overcome this problem,the applicant, as shown in FIGS. 4 to 8 inclusive, provides a base sheet30 which surrounds the major portion of the cylinder leaving a minorportion wherein a strip of adhesive tape (adhesive on both sidesthereof) is located. In this manner, since the adhesive strip 12 andbase sheet 30 are of equal thickness, the backing sheet 14 is providedwith a continuous, even, mounting surface.

With particular reference to FIGURE 5, it will be seen that opposed ends32 and 33 of base sheet 30 terminate in spaced relation to provide alongitudinally extending space for insertion of the adhesive strip 12.Following mounting of the base sheet and adhesive strip first indexmeans 10a are inscribed on the base sheet 30 preferably extending from aparticular shoulder 7.

One method of attaching the base sheet 30 to the cylinder is by firstapplying to the cylinder a sheet of doublefaced adhesive material aroundsame such that an adhesive base-sheet receiving surface is formed.However, any known and suitable adhesive could readily be employed foradherence of the base sheet to the cylinder.

After the first index means 10a have been inscribed, the backing sheet14 is mounted as hereinbefore described and the procedure followed isthe same as that set forth with reference to FIGS. 1 to 3. In thissecond embodiment, the base sheet 30 and adhesive strip 12 always remainwith the cylinder and other printing plate assemblies for differentprinting tasks can be set-up for repeated registration with the samemodified cylinder.

From the foregoing it will be obvious to those skilled in this fieldthat many modifications and changes may be effected without departingfrom the spirit and scope of the present invention and the applicantwishes to be limited only by the scope of the claims appended hereto.

What I claim as new and desire to protect by Letters Patent of theUnited States is:

1. The method of detachably mounting image-transfer plates on a printingmachine cylinder comprising the steps of tightly wrapping a base sheetaround a major portion of the cylinder and inserting a strip of adhesiveon the remaining minor portion to form a substantially even surfacearound said cylinder; tightly wrapping a flexible but otherwisesubstantially undeforrnable backing sheet around said base sheet,releasably adhering the terminal ends of said flexible backing sheet onsaid strip of adhesive; mounting the plates in selective spaced relationon the backing sheet; proving the resulting assembly for properalignment of the plates and then indexing the back sheet in registrationWith index means carried on the cylinder such that the backing sheet andplates thereon can be removed from and then remounted on the cylinder indesired registration therewith.

2. The method of claim 1 wherein the cylinder is provided with at leastone end shoulder, said shoulder acting as a guide during mounting of thebacking sheet.

3. In a printing cylinder and backing sheet assembly; a cylinder havinga backing sheet receiving surface, a raised shoulder at at least one endthereof; a strip of adhesive extending longitudinally of the backingsheet receiving surface, and first index means on the cylinder; anon-deformably flexible backing sheet carrying selectively alignedprinting plates thereon and mounted on the said receiving surface with aside edge of said backing sheet abutting the first raised shoulder ofthe cylinder; second index means on said hacking sheet for registrationwith said first index means, said backing sheet being tightly wrappedabout said receiving surface with longitudinal opposite ends thereof insubstantially edge-abutting relationship overlapping the aforementionedadhesive strip, said strip being interposed between the cylinder and theunderside of the backing sheet to releasably adhere said backing sheetto the cylinder such that the backing sheet assembly can be repeatedlyremoved and remounted on the cylinder in proper registration; saidassembly being further provided with a flexible, non-deformable basesheet adhered about the receiving surface and interposed :between saidreceiving surface and said backing sheet with longitudinal edges thereofsubstantially spaced apart and with the said strip of adhesive on thereceiving surface therebetween, said receiving surface beingsubstantially evenly built up by the thickness of the base sheet and theadhesive strip.

4. A printing cylinder and backing sheet assembly according to claim 3wherein the strip of adhesive comprises a strip of tape having adhesiveon both sides thereof with one such side removably adhered to thereceiving surface and the other side exposed for adherence to theaforementioned overlapping longitudinal ends of the backing sheetwhereby the said adhesive strip may be replaced upon deteriorationthereof.

References Cited UNITED STATES PATENTS 2,145,072 1/1939 Cooley 101415.1X 2,375,603 5/ 1945 Willard 101-415.1 3,108,538 10/ 1963 Barnes 101-41513,119,330 1/1964 Kunetka 101-426 3,128,700 4/ 1964 Kunetka 101--401.1 X

DAVID KLEIN, Primary Examiner.

3. IN A PRINTING CYLINDER AND BACKING SHEET ASSEMBLY; A CYLINDER HAVINGA BACKING SHEET RECEIVING SURFACE, A RAISED SHOULDER AT LEAST ONE ENDTHEREOF; A STRIP OF ADHESIVE EXTENDING LONGITUDINALLY OF THE BACKINGSHEET RECEIVING SURFACE, FIRST INDEX MEANS ON THE CYLINDER; ANON-DEFORMABLY FLEXIBLE BACKING SHEET CARRYING SELECTIVELY ALIGNEDPRINTING PLATES THEREON AND MOUNTED ON THE SAID RECEIVING SURFACE WITH ASIDE EDGE OF SAID BACKING SHEET ABUTTING THE FIRST RAISED SHOULDER OFTHE CYLINDER; SECOND INDEX MEANS ON SAID BACKING SHEET BEING TION WITHSAID FIRST INDEX MEANS, SAID BACKING SHEET BEING TIGHTLY WRAPPED ABOUTSAID RECEIVING SURFACE WITH LONGITUDINAL OPPOSITE ENDS THEREON INSUBSTANTIALLY EDGE-ABUTTING RELATIONSHIP OVERLAPPING THE AFOREMENTIONEDADHESIVE STRIP, SAID STRIP BEING INTERPOSED BETWEEN THE CYLINDER AND THEUNDERSIDE OF THE BACKING SHEET TO RELEASABLY ADHERE SAID BACKING SHEETTO THE CYLINDER SUCH THAT THE BACKING SHEET ASSEMBLY CAN BE REPEATEDLYREMOVED AND REMOUNTED ON THE CYLINDER IN PROPER REGISTRATION; ANDASSEMBY BEING FURTHER PROVIDED WITH A FLEXIBLE, NON-DEFORMABLE BASESHEET ADHERED ABOUT THE RECEIVING SURFACE AND INTERPOSED BETWEEN SAIDRECEIVING SURFACE AND SAID BACKING SHEET WITH LONGITUDINAL EDGES THEREOFSUBSTANTIALLY SPACED APART AND WITH THE SAID STRIP OF ADHESIVE ON THERECEIVING SURFACE THEREBETWEEN, SAID RECEIVING SURFACE BEINGSUBSTANTIALLY EVENLY BUILT UP BY THE THICKNESS OF THE BASE SHEET AND THEADHESIVE STRIP.